


Her Rules

by ForbiddenArchive



Series: Poll Stories 2020 [61]
Category: Persona 5
Genre: Brainwashing, F/F, Hypnosis, Mental Twinning, Transformation, Twinning
Language: English
Status: Completed
Published: 2020-12-01
Updated: 2020-12-01
Packaged: 2021-03-09 23:28:13
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,016
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/27824512
Author URL: https://archiveofourown.org/users/ForbiddenArchive/pseuds/ForbiddenArchive
Summary: Sae's shadow decides to play by the rules of the Phantom Thieves, changing her sister's heart by force.
Relationships: Niijima Makoto/Shadow Niijima Sae
Series: Poll Stories 2020 [61]
Series URL: https://archiveofourown.org/series/1594363
Kudos: 11





	Her Rules

**Author's Note:**

> Poll story for Week 48.

The Phantom Thieves of Hearts were on a roll. Little by little they were chipping away at the scum hiding in plain sight. And their next target, though no doubt as difficult as the rest of them, was still going to fall to their combined wit and might.

Or so they thought. While scoping out the Palace, preemptively making sure that they had everything properly planned out for their heist, something went wrong. Instead of them being the ones to instigate a heist, they found themselves deprived of a member. 

Niijima Makoto, the sister of the one they were supposed to fight, had disappeared not long after they entered the Metaverse. They barely got a chance to hear the girl scream before she was gone, abducted by the Shadows that patrolled the casino. This left them without one of their physical powerhouses, or any secret knowledge they could take advantage of to figure out a weakness for their latest mark.

And little did they know, that wasn’t the only issue that arose from the tables suddenly being turned on them. None of them could’ve ever anticipated what the Shadow that ruled the Palace would do to her dearest and unlawful sister…

\---

“Wake up, Makoto.”

A stern voice echoed through the ears of the younger Niijima, causing her eyes to flutter open slowly. She could feel a pulsating pain rushing through the back of her head, where she had been struck prior to falling unconscious. It meant that her eyesight was more than a little blurry, even as she tried to focus on the person who had addressed her.

“I said, wake up. Are you going to lie there until you die or are you going to listen and obey?” The stern voice asked again, this time grabbing the girl by the hair and yanking her onto her feet, forcing her eyes to open wide in response to the shock of pain melding with the sensations from before.

Makoto couldn’t believe what she saw. Her sister, the woman she looked up to, glaring down at her with nothing more than disdain. “Sis…” She muttered. Despite the gloomier and more sexually expressive look that the woman in front of her had, it was impossible for her to not recognize her sister.

“There we go. I thought you’d never react. Maybe my guards roughed you up a little too hard. I suppose I should punish them when I have the chance, but I think I can leave that to you when I’m done with you.” Sae, or rather her Shadow, dropped her sister and adjusted her dress ever slightly, dusting it off where the girl had rubbed up against her.

Her younger sister stumbled back and forth, her mind and her body still catching up with one another thanks to being unconscious just moments prior. “How did you know we were coming? We thought you couldn’t notice us…” She slurred her words a little, trying to regain her footing proper and enter a combat stance.

“You really think that I don’t notice the kind of tactics that thieves like you and the vermin you call friends employ? I know everything about the rules that you play by, Makoto. It’s only right for me to use those very same tactics, turning your little escapade on its head as you walk right back into my arms.”

Makoto grit her teeth and stomped down with one of her feet, clenching her fists as she composed herself as much as she could. “That’s cheating, you’d never do that!” She tried to get through to her with reason, something to make the real Sae pop to the surface…

“Cheating? I hold all the cards, Makoto! I follow my own rules, and use yours against you. And at the end, the house takes it all.” A wicked smile appeared on the Shadow’s face, laughing at the girl’s efforts to talk sense into her.

The younger Niijima couldn’t take the look of pure scorn on her sister’s face. Not like this. She had to fix her, and if that meant she’d have to beat her up, then-

Sae’s eyes narrowed sharply as she snapped her fingers, causing all of the strength to drain from the girl in a matter of seconds. In turn, the girl fell onto the floor and started panting like she had just run a marathon. “I told you, Makoto. I hold the cards. I don’t care what tricks you’ve been employing to steal hearts before. You won’t be stealing mine.” She scoffed, disgusted that the girl thought she could even prove to be a real danger to her.

Makoto took deep breaths, trying to regain her energy. But the more she breathed, the harder it became to rise back up. It was a wicked cycle. The more she tried to fight back, the harder the rules of the Palace forced her to obey. “Sis, please-”

“No.” Her protests were quickly shut down, as the scornful eye-shadowed woman slammed her heel into the ground. “As long as you continue to act against the rules, I will continue to reprimand you. I will continue to grind you into the pavement until you understand where you belong. And when you finally understand, then I’ll show mercy.” She said, running her gloved hand along her sister’s cheek…

A gesture that was very quickly turned against her, the younger sister headbutting that hand to try and show a little bit of defiance. Anything to try and get back on her feet. “You say you want us to follow the rules, why don’t you set a good example? Follow your own rules properly instead of breaking them!” 

“Rules are bent as I please!” Sae shouted in response, before closing her eyes and smiling from ear to ear. “Very well. If you want to follow the same rules as me, I suppose I can find a reason for you to do so.”

  
Without missing a beat, a picture of her normal self appeared in between her fingertips. “Your tactics require you to steal a treasure precious to your mark. Who’s to say I can’t force a treasure upon you and see you change that way? I’d be playing by the same rules as you. I’m sure you’ll understand.”

Makoto struggled against her own lack of energy, only briefly letting out a gasp and a scream as a myriad of sensations pulsated through her all at once. The picture that her sister held was slowly sinking into her heart, as her bodysuit quickly started to melt off her. Her perception of herself was at risk.

The further into her it went, the more her body started to take on a similar look to that of her sister. The tight bodysuit meant for a rough and ready biker was replaced with a dress that reached all the way down to her ankles yet exposed so much more than the suit ever could’ve, with her thighs shown to the world around her.

She let out a moan as the picture sank further in, her legs gradually getting covered in a fishnet that ended in a nice set of dominant heels wrapping around her feet. A bit of netting weaved between the two sides of her dress as well, exposing her meager breasts to the world as her arms were left utterly uncovered.

The older sister licked her lips in anticipation as she watched her sister transform further and further, her arms getting covered in the same gloves that she wore. If one just looked at the two sisters, it’d be hard to tell who was who based on just their outfits since they were completely identical at this point. The only difference being their eyes and their hair, and when the picture finished sinking into the younger sister, that would be gone just as well.

Makoto kept on moaning as a bit of eyeshadow spread around her eyes, as well as deep black lipstick being coloured onto her lips. Her hair grew longer, just as long as her sister’s, all while her body continued to pulsate and throb with delight. Her individuality was being stripped from her, forced to dress and look just like her sister down to the attire and hairstyle…

And that was just her looks. Her mind was still trying to struggle. Still trying to stay its own. But the more the image of her sister started to sink in, the harder it became to distinguish who was who on the inside. She was Niijima Makoto, right? The thoughts inside of her head attempted to stay coherent, but the longer that picture stayed inside her, the harder it became to keep it true…

Thoughts about her time with her friends grew more distasteful. She shouldn’t be spending time with them. She should be spending time studying. Working to be the best that she could. Just like her sister. That was what was important to her, important to the both of them. They had to stand on their own two feet, instead of leaning on everyone else.

Makoto’s expression gradually grew more and more stern, just like the one on her sister’s face. She imagined the long and hard hours of studying to get into a position that let her have all the power she needed. The amount of work that she had to do to get there. Everything that needed to come together before she even came close to being as good as her sister…

Her sense of self worth was plummeting. Everything that she should’ve been enjoying was going up in smoke, replaced with a crushing need to be like her sister. Be like the woman who took care of her. Show her gratitude for what she should’ve been doing all this time. That way, the two of them could live like a proper family once more…

No. She didn’t need to be like her sister. She should be like herself. Like Sae Niijima. Of course, that was too obvious. If she even tried to act like her sister, then she’d be a failure. A joke that dared think the vermin that didn’t try to excel in life were her friends. Being like that was futile. She needed to stand atop, alongside her other self.

Makoto’s eyes turned into Sae’s, as she stood up without any fatigue washing over her. Because she wasn’t an intruder within the woman’s palace any longer. She was a part of it. She was the owner, just like Sae.

Because she was Sae.

The two identical sisters smiled at one another, their gloved hands meeting their cheeks as they let their lips meet and their love for one another flow for just a brief moment. 

All while the seeds that had been planted inside the girl’s heart would bloom in the real world.

\---

That night in the Niijima household, things were wonderfully quiet. There wasn’t an argument that the two needed to have, as everything was already cleaned by the time the older sister came home. 

Dinner was nice and brief as well, the two chatting about the work that they each had done. Whether it was the cases that Sae had presided over, or the subjects that Makoto had buried her head in. The younger sister even shared her distaste for the Phantom Thieves, having seen things her sister’s way and understanding that it was the truth. Both of them shared a laugh, happy that they saw eye to eye again and used all of their time to sink themselves as deep into work as they could.

When it was time to go to bed, a weekend sitting on the horizon, Sae peeked into her sister’s room expecting her to be doing anything but studying. But a smile crept onto her face instead when she saw that her sister was still studying, making up for lost time as much as she possibly could..

Thus, their bond as sisters mended. Perhaps a little too tightly, as the younger sister had begun to style her hair in the same way as her older sister…


End file.
